How to point to a pointer variable

Question

Is there a way to point to the pointer variable instead of it's address space so that it can be changed to NULL. Something like this. Apologies for the poor question I can't think of a better way of expressing what I'm trying to do. Thanks.

typedef struct Node
{
    int val;
    struct Node *r;
    struct Node *l;
} Node;

Node* del(Node *N, int v)
{
    Node *n = N;
    Node **p = NULL;

    while (n != NULL)
    {
        if (something)
        {
            p = n.r;
            n = n->r;
        }
        else {
            p = n.l;
            n = n->l;
        }

        free(n);
        *p = NULL;
    }
}

Carl Norum · Accepted Answer · 2013-07-15 17:43:08Z

3

You can use & on a pointer just like on any other variable. In your case, it looks like you might want to change del to:

Node *del(Node **N, int v)

And then call it like:

x = del(&someNode, 12);

answered Jul 15, 2013 at 17:43

Carl Norum

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2 Comments

user2579943 Over a year ago

And dereference with an additional *.

Eiyrioü von Kauyf Over a year ago

and use all the other regular pointer ops for the most part. Nested pointers are a very... fun thing :)

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